"The work that you do is important," Zucker wrote in a memo. "And that is why we are so vigilantly protective of our role as journalists."

A few hours after President Trump attacked CNN chief White House correspondent Jim Acosta as "rude" and "terrible" during a press conference, network president Jeff Zucker told employees that CNN stands behind them.

"I want you to know that we have your backs," Zucker said in the memo, which was obtained by The Hollywood Reporter. "That this organization believes fiercely in the protections granted to us by the First Amendment, and we will defend them, and you, vigorously, every time."

Trump, and his spokesperson, White House press secretary Sarah Huckabee Sanders, have long insulted Acosta, but the president's attack on Wednesday was his most personal yet.

"CNN should be ashamed of itself having you working for them," Trump told Acosta. "You are a rude, terrible person. You shouldn't be working for CNN. You're a very rude person. The way you treat Sarah Huckabee Sanders is horrible. You shouldn't treat people that way."

In the memo, Zucker said, "The work that you do is important. It matters. And that is why we are so vigilantly protective of our role as journalists."

Zucker also said he wanted to make sure all employees saw the statement the network put out in response to Trump's attacks on the network, which he called "the enemy of the people" (when it produces "fake news").

"This president’s ongoing attacks on the press have gone too far," the statement read. "They are not only dangerous, they are disturbingly un-American. While President Trump has made it clear he does not respect a free press, he has a sworn obligation to protect it. A free press is vital to democracy, and we stand behind Jim Acosta and his fellow journalists everywhere."

As he did after the network was targeted with a mail bomb, Zucker thanked his employees for their hard work and focus, citing their "amazing contributions, hours and hours of work with no sleep, days on the road, and countless stories produced."

Zucker concluded: "Thank you for what you did for the midterm coverage. Thank you for what you do every day. Congratulations on yesterday's enormous success."